1. Field of the Invention
The present invention relates to an inspection contact structure to contact with an object electrically to be inspected to inspect electric properties of the object to be inspected, and a probe card.
2. Description of the Related Art
Inspection of electric properties of an electronic circuit such as an IC, LSI, or the like formed, for example, on a semiconductor wafer is performed by bringing, for example, a plurality of probe needles arranged on the lower surface of a probe card into electrical contact with electrode pads of the electronic circuit on the wafer. Therefore, the probe needles need to be arranged in alignment with the positions of the respective electrode pads.
However, the pattern of the electronic circuit has become finer in which the electrode pads have been made finer and intervals between the electrode pads have become smaller. This requires formation of fine contact portions at a narrow pitch, such as those with a width dimension of 100 μm or less and at a pitch of 180 μm or less. Hence, use of an anisotropic conductive sheet instead of the probe needles is proposed (Japanese Patent Application Laid-open Publication No. H03-196416 (U.S. Pat. No. 3,038,859). The anisotropic conductive sheet is a sheet having a plurality of elastic conductive portions protruding from one surface of the sheet being an insulating portion, in which the conductive portions can be formed very fine at a narrow pitch.
However, when the above-described anisotropic conductive sheet is simply used, the conductive portions have limitations in dimension in the height direction because the conductive portions are formed fine at a narrow pitch, resulting in small displacement in the height direction presented by the elasticity of the conductive portions. As a result, the conductive portions cannot absorb, by their elasticity, variations in height of a number of electrode pads on the wafer surface, thus causing unstable contact between the conductive portions and the electrode pads within the wafer surface. Further, the inclination and distortion on the probe card side occurring due to attachment or thermal expansion of the probe card cannot be sufficiently absorbed by the elasticity of the conductive portions, resulting in unstable contact of the electrode pads within the wafer surface.